Hydration and exercise

Hydration represents one of the most important parts of training, since if it is not adequate, performance can decline significantly, and even lead to health problems.

Dehydration refers to the process of losing water, which leads to a state of hypohydration, that is, below normal levels of body water. During physical activity, people normally reach different levels of body water loss, which can occur voluntarily and / or involuntarily.

Hydration is not only a balance of fluids, but also refers to the volume, composition and distribution of fluids in the body. All these characteristics depend to a great extent on the time, the nature and the type of stress that this induction to dehydration produces.

Water is essential to maintain homeostasis at the cellular level. If we are faced with low levels of body water, hypohydration, cardiovascular, thermal, metabolic and immune stress can be increased. Dehydration reduces cognitive, motor, and aerobic abilities.

But how much water do we have to lose to be considered dehydration? According to the ACSM (American College of Shorts Medicine) position, the reduction in total body water should be greater than or equal to 2% of body mass.

It is very important to take into account the optimal levels of water for thermoregulation, since the loss of fluids can cause hyperthermia, and therefore more easily bring heat strokes, lipothymias, etc.

But as mentioned above, not only the total water volume must be taken into account, but the composition of these fluids, since low sodium levels can lead to hyponatremia. Hyponatremia can also occur due to excess hydration.

Drinking fluids with a higher amount of electrolytes, such as sodium, increases the sensation of thirst, causing a greater intake of fluids, with which rehydration comes earlier, balancing total body water, extracellular volume, intracellular volume, volume plasma, plasma osmorality, and aldosterone and angiotensin levels.

As a summary, we are going to list some of the situations that occur in different situations due to hydration problems:

Acutely what happens if we drink little (hypohydration):

• The chances of suffering a heat stroke increase.
• Increases physiological stress.
• Lowers mood.
• Cognitive abilities are reduced.
• Discomfort or distress occurs due to thirst.
• Chances of cramping increase.
• Increase fatigue.

Chronically, what could happen if we drink little (hypohydration):

• It could lower the mood.
• They could decrease cognitive abilities.
• Glycogenesis could be reduced.
• Protein synthesis could be reduced.
• Metabolic problems could occur.
• They increase the chances of suffering from cardiovascular diseases.
• There are more risks for urinary tract infections.
• Kidney stones may develop.
• You are more likely to suffer from chronic kidney problems.
• Discomfort or distress occurs due to thirst.

Acutely what happens if we drink too much (hyperhydration):

• Urination increases.
• Discomfort in the bladder
• Hyponatremia could occur.

Chronically what happens if we drink too much (hyperhydration):

• Decreases renal concentration capacity.

But when do we drink? When are we thirsty? Thirst will largely depend on whether hypovolema, hyperosmolarity or increased angiogensin II has occurred. The former condition leads to thirst due to certain brain regions being stimulated, while the latter leads to fluid retention and increased blood pressure. Therefore, thirst is not the only indicator that we should ingest fluids.

Do not forget to drink regularly, increase your fluid intake when you exercise and, above all, when you do it in hot environments. Of course, in FAST drink before, during and after your session, even if it is 20 minutes you know that they are intense and your body needs an extra water to recover.

References:

Stachenfeld. The Interrelationship of Research in the Laboratory and the Field to Assess Hydration Status and Determine Mechanisms Involved in Water Regulation During Physical Activity. SportsMed.

Cotter et al. Ares we being drownes in hydration advice? Thirsty for more? Extreme Physiology and Medicine.